Perhaps the most-cited downside of renewable energy is that wind or sunlight might not always be available when the electrical grid demands it. As they say in the industry, it’s not “dispatchable”. A large enough grid can mitigate this somewhat by moving energy long distances or by using various existing storage methods like pumped storage, but for the time being some amount of dispatchable power generation like nuclear, fossil, or hydro power is often needed to backstop the fundamental nature of nature. As prices for wind and solar drop precipitously, though, the economics of finding other grid storage solutions get better. While the current focus is almost exclusively dedicated to batteries, another way of solving these problems may be using renewables to generate hydrogen both as a fuel and as a means of grid storage.
HYDROGEN AS FUEL
Provided that there’s a supply of water nearby, turbines, solar farms, or even excess electricity on the grid, hydrogen can be produced by electrolyis. This hydrogen could then be transported for use as a fuel, thus decoupling the need for a renewable resource like a wind farm to be physically connected to the bulk electric grid. Often wind resources are extremely far from population centers so an alternative energy delivery system that doesn’t involve building long transmission lines could make sense in some situations. Some experiments find that hydrogen can be pumped in much the same way that natural gas currently is, although it doesn’t have the same energy content per unit volume. Hydrogen could alternatively be used locally as an energy storage method as well, using excess energy to produce hydrogen during situations where the dispatcher would otherwise curtail the wind farm, with the hydrogen stored and used later to generate electricity at a time when the wind isn’t blowing. This could be a viable alternative to battery storage at wind farms, especially as current forecasts expect a significantly large percentage of all ne batteries to be used in electric vehicles.
Producing hydrogen by electrolysis is not currently done on a large scale because it’s not the most efficient way of producing hydrogen, but there are two reasons for that which are slowly becoming less relevant. First, with an arbitrarily large amount of free renewable energy the cost of that energy becomes less of an issue. Second, most industrial hydrogen is currently produced using fossil fuels, which is not a great long-term method when it comes to climate change. But this may be an increasingly useful avenue of exploration in the years to come.
HYDROGEN AS AN INTERMEDIARY
Hydrogen does have a number of downsides, though. The obvious issues of dealing with flammable gasses aside, hydrogen molecules are extremely tiny and are thus difficult to contain in traditional storage vessels. Any small imperfection will cause the gas to leak out much more rapidly than other fuels. Much to Toyota’s chagrin, as they are deeply invested in hydrogen echnology with little to show for it, there is also no developed hydrogen infrastructure largely because electricity is far superior as a energy transportation method. To mitigate these problems, however, a hydrogen-producing wind or solar farm could be put to use producing ammonia instead, with the electrolytic hydrogen only used as an intermediary instead of using it as a fuel source directly. This “green ammonia” can be burned directly or used in fuel cells for electricity production, and is much less of an escape artist than pure hydrogen.
Another downside to generating hydrogen or ammonia with renewable energy is that it requires a large amount of water, which may be less available as climate change progresses in a concerning number of areas other than the open ocean. However, in areas with enormous reserves such as the Great Lakes region in North America, the Amazon River Basin in South America, or the Lake Baikal area in Siberia, this could be a drop in the bucket. Not every plce on earth lends itself to wind or solar energy production, but in general wind may be preferred because it tends to have a higher capacity factor than solar and uses less land area.
OTHER USES FOR RENEWABLE ENERGY
Wind turbines can still be put to more direct use than generating fuel or electricity, as any 17th century Netherlander would be able to confirm. They’re often used to directly pump water from wells for livestock in places without electricity just as they once pumped water to create the iconic Dutch polders. They can also be used to directly generate heat with no electric intermediary stage, which we covered briefly in this article. Although this is not in widespread use, it’s a conceivable future where wind technology is more easily-accessible and heating needs aren’t able to be met by more traditional sources.
Of course, as a global society we’ve largely settled on electricity as an energy transportation method for good reason instead of using flammable gasses like hydrgen. It’s instantaneous, efficient, and versatile, so anything looking to generate energy in other forms is going to be an extreme outlier. But as we hopefully transition to a post-fossil society, electrolytic hydrogen production methods may gain more widespread adoption.
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Tagged green hydrogen, hydrogen, wind power
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